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The instability of the ocean to Langmuir circulations

Published online by Cambridge University Press:  20 April 2006

S. Leibovich
Affiliation:
Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, New York 14853
S. Paolucci
Affiliation:
Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, New York 14853 Present address: Sandia National Laboratories, Livermore, California 94550.

Abstract

It has been proposed that Langmuir circulations arise as an instability of the equations describing the Eulerian-mean flow in bodies of water supporting surface waves and subject to an applied wind stress. In infinitely deep density-stratified water, the solution of an appropriate initial-value problem is a unidirectional, time-dependent current. The stability of this current to two-dimensional (roll) disturbances is investigated by an energy analysis and by linear theory. It is found that the energy stability estimates and linear stability limits are very close, showing that subcritical instability, if it occurs, is limited to a very narrow region in parameter space. According to the present results, conditions typically occurring in the ocean are highly unstable to the Langmuir circulation instability.

Type
Research Article
Copyright
© 1981 Cambridge University Press

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References

Bellman, R. 1969 Stability Theory of Differential Equations Dover.
Cesari, L. 1971 Asymptotic Behavior and Stability Problems in Ordinary Differential Equations, 3rd ed. Springer.
Craik, A. D. D. 1977 The generation of Langmuir circulations by an instability mechanism. J. Fluid Mech. 81, 209223.Google Scholar
Craik, A. D. D. & Leibovich, S. 1976 A rational model for Langmuir circulations. J. Fluid Mech. 73, 401426.Google Scholar
Dudis, J. J. & Davis, S. H. 1971a Energy stability of the buoyancy boundary layer. J. Fluid Mech. 47, 381403.Google Scholar
Dudis, J. J. & Davis, S. H. 1971b Energy stability of the Ekman boundary layer. J. Fluid Mech. 47, 405413.Google Scholar
Faller, A. J. 1978 Experiments with controlled Langmuir circulations. Science 201, 618620.Google Scholar
Faller, A. J. & Caponi, E. A. 1978 Laboratory studies of wind driven Langmuir circulations. J. Geophys. Res. 83, 36173633.Google Scholar
Finlayson, B. A. 1972 The Method of Weighted Residuals and Variational Principles Academic.
Foster, T. D. 1965 Stability of a homogeneous fluid cooled uniformly from above. Phys. Fluids 8, 12491257.Google Scholar
Foster, T. D. 1968 Effect of boundary conditions on the onset of convection. Phys. Fluids 11, 12571262.Google Scholar
Galdi, G. P. & Rionero, S. 1977 On magnetohydrodynamic motions in unbounded domains: stability and uniqueness. Ann. Mat. Pura & Appl. 115, 119154.Google Scholar
Gumerman, R. J. & Homsy, G. M. 1975 The stability of uniformly accelerated flows with application to convection driven by surface tension. J. Fluid Mech. 68, 191207.Google Scholar
Homsy, G. M. 1973 Global stability of time-dependent flows: impulsively heated or cooled liquid layers. J. Fluid Mech. 60, 129139.Google Scholar
Joseph, D. D. 1976a Stability of Fluid Motions I. Springer.
Joseph, D. D. 1976b Stability of Fluid Motions II. Springer.
Langmuir, I. 1938 Surface motion of water induced by wind. Science 87, 119123.Google Scholar
Leibovich, S. 1977a On the evolution of the system of wind drift currents and Langmuir circulations in the ocean. Part 1. Theory and averaged current. J. Fluid Mech. 79, 715743.Google Scholar
Leibovich, S. 1977b Convective instability of stably stratified water in the ocean. J. Fluid Mech. 82, 561585.Google Scholar
Leibovich, S. 1980 On wave-current interaction theories of Langmuir circulations. J. Fluid Mech. 99, 715724.Google Scholar
Leibovich, S. & Paolucci, S. 1980 The Langmuir circulation instability as a mixing mechanism in the upper ocean. J. Phys. Ocean. 10, 186207.Google Scholar
Leibovich, S. & Radhakrishnan, K. 1977 On the evolution of the system of wind drift currents and Langmuir circulations in the ocean. Part 2. Structure of the Langmuir vortices. J. Fluid Mech. 80, 481507.Google Scholar
Wankat, P. C. & Homsy, G. M. 1977 Lower bounds for the onset time of instability in heated layers. Phys. Fluids 20, 12001201.Google Scholar